File locations are now ranges.

2025-10-10 16:26:03 -07:00
parent 6b9da23478
commit 2af6ef1c1b
11 changed files with 167 additions and 150 deletions
--- a/newt-vscode/src/extension.ts
+++ b/newt-vscode/src/extension.ts
@@ -109,21 +109,21 @@ export function activate(context: vscode.ExtensionContext) {
            }
            console.log("top data", topData);
          }
-          const match = line.match(
-            /(INFO|WARN|ERROR) at (.*):\((\d+), (\d+)\):\s*(.*)/
-          );
+            const match = line.match(
+            /(INFO|WARN|ERROR) at (.*):\((\d+):(\d+)-(\d+):(\d+)\):\s*(.*)/
+            );
          if (match) {
-            let [_full, kind, file, line, column, message] = match;
-            let lnum = Number(line) - 1;
-            let cnum = Number(column) - 1;
-            if (file !== fileName) lnum = cnum = 0;
-
+            let [_full, kind, file, line, column, eline, ecol, message] = match;
+            let lnum = +line - 1;
+            let cnum = +column - 1;
+            let elnum = +eline - 1;
+            let ecnum = +ecol - 1;
            let start = new vscode.Position(lnum, cnum);
-            // we don't have the full range, so grab the surrounding word
-            let end = new vscode.Position(lnum, cnum + 1);
-            let range =
-              document.getWordRangeAtPosition(start) ??
-              new vscode.Range(start, end);
+            let end = new vscode.Position(elnum, ecnum);
+            let range = new vscode.Range(start, end);
+            if (file !== fileName) {
+              range = new vscode.Range(new vscode.Position(0,0), new vscode.Position(0,0));
+            }
            // anything indented after the ERROR/INFO line are part of
            // the message
            while (lines[i + 1]?.match(/^(  )/)) message += "\n" + lines[++i];
--- a/playground/src/main.ts
+++ b/playground/src/main.ts
@@ -440,18 +440,20 @@ const processOutput = (
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i];
    const match = line.match(
-      /(INFO|ERROR) at ([^:]+):\((\d+), (\d+)\):\s*(.*)/
+      /(INFO|ERROR) at ([^:]+):\((\d+):(\d+)-(\d+):(\d+)\):\s*(.*)/
    );
    if (match) {
-      let [_full, kind, file, line, col, message] = match;
-      let lineNumber = +line;
-      let column = +col;
+      let [_full, kind, file, line, col, eline, ecol, message] = match;
+      let startLineNumber = +line;
+      let startColumn = +col;
+      let endLineNumber = +eline;
+      let endColumn = +ecol
      // FIXME - pass the real path in
      if (fn && fn !== file) {
-        lineNumber = column = 0;
+        startLineNumber = startColumn = 0;
      }
      // we don't have the full range, so grab the surrounding word
-      let endColumn = column + 1;
+      // let endColumn = startColumn + 1;

      // heuristics to grab the entire message:
      // anything indented
@@ -460,13 +462,13 @@ const processOutput = (
      while (lines[i + 1]?.match(/^(  )/)) {
        message += "\n" + lines[++i];
      }
-      if (kind === "ERROR" || lineNumber)
+      if (kind === "ERROR" || startLineNumber)
        markers.push({
          severity: kind === "ERROR" ? "error" : "info",
          message,
-          startLineNumber: lineNumber,
-          endLineNumber: lineNumber,
-          startColumn: column,
+          startLineNumber,
+          endLineNumber,
+          startColumn,
          endColumn,
        });
    }
--- a/scripts/test
+++ b/scripts/test
@@ -18,7 +18,7 @@ for fn in tests/*.newt ; do
  if [ -f ${fn}.fail ]; then
    if ! diff -q tmp/${bn}.compile ${fn}.fail; then
        echo "Compile failure mismatch for $fn"
-        diff tmp/${bn}.comp ${fn}.fail
+        diff ${fn}.fail tmp/${bn}.compile
        failed=$((failed + 1))
        continue
    fi
@@ -38,7 +38,7 @@ for fn in tests/*.newt ; do
    fi
    if ! diff -q tmp/${bn}.out ${fn}.golden; then
      echo "Output mismatch for $fn"
-      diff -q tmp/${bn}.out ${fn}.golden
+      diff ${fn}.golden tmp/${bn}.out
      failed=$((failed + 1))
    fi
  fi
--- a/src/Lib/Common.newt
+++ b/src/Lib/Common.newt
@@ -5,6 +5,32 @@ import Data.String
 import Data.Int
 import Data.SortedMap

+record Bounds where
+  constructor MkBounds
+  startLine : Int
+  startCol : Int
+  endLine : Int
+  endCol : Int
+
+-- FIXME we should handle overlap and out of order..
+instance Add Bounds where
+  a + b = MkBounds a.startLine a.startCol b.endLine b.endCol
+
+instance Eq Bounds where
+  (MkBounds sl sc el ec) == (MkBounds sl' sc' el' ec') =
+      sl == sl'
+   && sc == sc'
+   && el == el'
+   && ec == ec'
+
+record WithBounds ty where
+  constructor MkBounded
+  val : ty
+  bounds : Bounds
+
+emptyBounds : Bounds
+emptyBounds = MkBounds 0 0 0 0
+
 -- l is environment size, this works for both lvl2ix and ix2lvl

 range : Int → Int → List Int
@@ -74,19 +100,19 @@ instance ToJSON Int where
 record FC where
  constructor MkFC
  file : String
-  start : (Int × Int)
+  bnds : Bounds


 instance ToJSON FC where
-  toJson (MkFC file (line,col)) = JsonObj (("file", toJson file) :: ("line", toJson line) :: ("col", toJson col) :: Nil)
+  toJson (MkFC file (MkBounds line col endline endcol)) = JsonObj (("file", toJson file) :: ("line", toJson line) :: ("col", toJson col) :: ("endline", toJson endline) :: ("endcol", toJson endcol):: Nil)


 fcLine : FC -> Int
-fcLine (MkFC file (l, c)) = l
+fcLine fc = fc.bnds.startLine


 fcCol : FC -> Int
-fcCol (MkFC file (l, c)) = c
+fcCol fc = fc.bnds.startCol


 class HasFC a where
@@ -96,7 +122,10 @@ primNS : List String
 primNS = ("Prim" :: Nil)

 emptyFC : FC
-emptyFC = MkFC "" (0,0)
+emptyFC = MkFC "" (MkBounds 0 0 0 0)
+
+emptyFC' : String → FC
+emptyFC' fn = MkFC fn (MkBounds 0 0 0 0)

 -- Error of a parse

@@ -119,7 +148,8 @@ data Error
  | Postpone FC QName String

 instance Show FC where
-  show (MkFC file (l,c)) = "\{file}:(\{show $ l + 1}, \{show $ c + 1})"
+  -- We add one to the end column so it points after the end, which seems to be what Idris does
+  show (MkFC file (MkBounds l c el ec)) = "\{file}:(\{show $ l + 1}:\{show $ c + 1}-\{show $ el + 1}:\{show $ ec + 2})"


 showError : String -> Error -> String
--- a/src/Lib/Parser.newt
+++ b/src/Lib/Parser.newt
@@ -9,6 +9,8 @@ import Lib.Syntax
 import Lib.Token
 import Lib.Types

+-- TODO - anywhere this says getPos, we probably have to fix bounds?  It is token sized though.
+
 lazy : ∀ a. (Unit → Parser a) → Parser a
 lazy pa = pa MkUnit

@@ -61,10 +63,8 @@ interp = do
  token EndInterp
  pure tm

-
 interpString : Parser Raw
 interpString = do
-  -- fc <- getPos
  ignore $ token StartQuote
  part <- term
  parts <- many (stringLit <|> interp)
--- a/src/Lib/Parser/Impl.newt
+++ b/src/Lib/Parser/Impl.newt
@@ -15,13 +15,13 @@ TokenList = List BTok
 -- Result of a parse

 data Result : U -> U where
-  OK : ∀ a. a -> (toks : TokenList) -> (com : Bool) -> Operators -> Result a
-  Fail : ∀ a. Bool -> Error -> (toks : TokenList) -> (com : Bool) -> Operators -> Result a
+  OK : ∀ a. a -> Bounds -> (toks : TokenList) -> (com : Bool) -> Operators -> Result a
+  Fail : ∀ a. Bool -> Error -> Bounds -> (toks : TokenList) -> (com : Bool) -> Operators -> Result a


 instance Functor Result where
-  map f (OK a toks com ops) = OK (f a) toks com ops
-  map _ (Fail fatal err toks com ops) = Fail fatal err toks com ops
+  map f (OK a last toks com ops) = OK (f a) last toks com ops
+  map _ (Fail fatal err last toks com ops) = Fail fatal err last toks com ops

 -- So sixty just has a newtype function here now (probably for perf).
 -- A record might be more ergonomic, but would require a record impl before
@@ -34,108 +34,97 @@ instance Functor Result where
 -- Since I've already built out the pratt stuff, I guess I'll
 -- leave it in the parser for now

-- This is a Reader in FC, a State in Operators, Commit flag, TokenList
+-- This is a Reader in FC (indent), a State in Operators, Commit flag, TokenList
+-- Using FC to pass around the fileName, but the indent only uses line and column
+data Parser a = P (Bounds -> TokenList -> Bool -> Operators -> (lc : FC) -> Result a)


-data Parser a = P (TokenList -> Bool -> Operators -> (lc : FC) -> Result a)
-
-
-runP : ∀ a. Parser a -> TokenList -> Bool -> Operators -> FC -> Result a
+runP : ∀ a. Parser a -> Bounds -> TokenList -> Bool -> Operators -> FC -> Result a
 runP (P f) = f

-- FIXME no filename, also half the time it is pointing at the token after the error
+-- FIXME half the time it is pointing at the token after the error
 perror : String -> TokenList -> String -> Error
-perror fn Nil msg = E (MkFC fn (0,0)) msg
-perror fn ((MkBounded val (MkBounds line col _ _)) :: _) msg = E (MkFC fn (line,col)) msg
+perror fn Nil msg = E (emptyFC' fn) msg
+perror fn ((MkBounded val bnds) :: _) msg = E (MkFC fn bnds) msg


 parse : ∀ a. String -> Parser a -> TokenList -> Either Error a
-parse fn pa toks = case runP pa toks False emptyMap (MkFC fn (-1,-1)) of
-  Fail fatal err toks com ops => Left err
-  OK a Nil _ _ => Right a
-  OK a ts _ _ => Left (perror fn ts "Extra toks")
+parse fn pa toks = case runP pa emptyBounds toks False emptyMap (MkFC fn (MkBounds -1 -1  -1 -1)) of
+  Fail fatal err last toks com ops => Left err
+  OK a _ Nil _ _ => Right a
+  OK a _ ts _ _ => Left (perror fn ts "Extra toks")

 -- Intended for parsing a top level declaration

 partialParse : ∀ a. String -> Parser a -> Operators -> TokenList -> Either (Error × TokenList) (a × Operators × TokenList)
-partialParse fn pa ops toks = case runP pa toks False ops (MkFC fn (0,0)) of
-  Fail fatal err toks com ops => Left (err, toks)
-  OK a ts _ ops => Right (a,ops,ts)
-
-- I think I want to drop the typeclasses for v1
-
+partialParse fn pa ops toks = case runP pa emptyBounds toks False ops (emptyFC' fn) of
+  Fail fatal err last toks com ops => Left (err, toks)
+  OK a last toks _ ops => Right (a,ops,toks)

 try : ∀ a. Parser a -> Parser a
-try (P pa) = P $ \toks com ops col => case pa toks com ops col of
-  (Fail x err toks com ops) => Fail x err toks False ops
+try (P pa) = P $ \last toks com ops col => case pa last toks com ops col of
+  (Fail x err last toks com ops) => Fail x err last toks False ops
  res => res


 fail : ∀ a. String -> Parser a
-fail msg = P $ \toks com ops col => Fail False (perror col.file toks msg) toks com ops
+fail msg = P $ \last toks com ops col => Fail False (perror col.file toks msg) last toks com ops


 fatal : ∀ a. String -> Parser a
-fatal msg = P $ \toks com ops col => Fail True (perror col.file toks msg) toks com ops
+fatal msg = P $ \last toks com ops col => Fail True (perror col.file toks msg) last toks com ops


 getOps : Parser (Operators)
-getOps = P $ \ toks com ops col => OK ops toks com ops
+getOps = P $ \last toks com ops col => OK ops last toks com ops


 addOp : String -> Int -> Fixity -> Parser Unit
-addOp nm prec fix = P $ \ toks com ops col =>
+addOp nm prec fix = P $ \ last toks com ops col =>
  let parts = split nm "_" in
  case parts of
-    "" :: key :: rule => OK MkUnit toks com (updateMap key (MkOp nm prec fix False rule) ops)
-    key :: rule => OK MkUnit toks com (updateMap key (MkOp nm prec fix True rule) ops)
-    Nil => Fail True (perror col.file toks "Internal error parsing mixfix") toks com ops
-
-
-
+    "" :: key :: rule => OK MkUnit last toks com (updateMap key (MkOp nm prec fix False rule) ops)
+    key :: rule => OK MkUnit last toks com (updateMap key (MkOp nm prec fix True rule) ops)
+    Nil => Fail True (perror col.file toks "Internal error parsing mixfix") last toks com ops

 instance Functor Parser where
-  map f (P pa) = P $ \ toks com ops col => map f (pa toks com ops col)
+  map f (P pa) = P $ \ last toks com ops col => map f (pa last toks com ops col)


 instance Applicative Parser where
-  return pa = P (\ toks com ops col => OK pa toks com ops)
-  P pab <*> P pa = P $ \toks com ops col =>
-    case pab toks com ops col of
-      Fail fatal err toks com ops => Fail fatal err toks com ops
-      OK f toks com ops =>
-        case pa toks com ops col of
-          (OK x toks com ops) => OK (f x) toks com ops
-          (Fail fatal err toks com ops) => Fail fatal err toks com ops
+  return pa = P (\ last toks com ops col => OK pa last toks com ops)
+  P pab <*> P pa = P $ \last toks com ops col =>
+    case pab last toks com ops col of
+      Fail fatal err last toks com ops => Fail fatal err last toks com ops
+      OK f last toks com ops =>
+        case pa last toks com ops col of
+          (OK x last toks com ops) => OK (f x) last toks com ops
+          (Fail fatal err last toks com ops) => Fail fatal err last toks com ops

 -- Second argument lazy so we don't have circular refs when defining parsers.

 instance Alternative Parser where
-  (P pa) <|> (P pb) = P $ \toks com ops col =>
-    case pa toks False ops col of
-      OK a toks' _ ops => OK a toks' com ops
-      Fail True  err toks' com ops  => Fail True err toks' com ops
-      Fail fatal err toks' True ops => Fail fatal err toks' True ops
-      Fail fatal err toks' False ops => pb toks com ops col
+  (P pa) <|> (P pb) = P $ \last toks com ops col =>
+    case pa last toks False ops col of
+      OK a last' toks' _ ops => OK a last' toks' com ops
+      Fail True  err last' toks' com ops  => Fail True err last' toks' com ops
+      Fail fatal err last' toks' True ops => Fail fatal err last' toks' True ops
+      Fail fatal err last' toks' False ops => pb last toks com ops col


 instance Monad Parser where
  pure = return
-  bind (P pa) pab = P $ \toks com ops col =>
-    case pa toks com ops col of
-      (OK a toks com ops) => runP (pab a) toks com ops col
-      (Fail fatal err xs x ops) => Fail fatal err xs x ops
+  bind (P pa) pab = P $ \last toks com ops col =>
+    case pa last toks com ops col of
+      (OK a last toks com ops) => runP (pab a) last toks com ops col
+      (Fail fatal err last toks x ops) => Fail fatal err last toks x ops


 satisfy : (BTok -> Bool) -> String -> Parser String
-satisfy f msg = P $ \toks com ops col =>
+satisfy f msg = P $ \last toks com ops col =>
  case toks of
-    (t :: ts) => if f t then OK (value t) ts True ops else Fail False (perror col.file toks "\{msg} at \{show t.val.kind}:\{value t}") toks com ops
-    Nil => Fail False (perror col.file toks "\{msg} at EOF") toks com ops
-
-
-commit : Parser Unit
-commit = P $ \toks com ops col => OK MkUnit toks True ops
+    (t :: ts) => if f t then OK (value t) t.bounds ts True ops else Fail False (perror col.file toks "\{msg} at \{show t.val.kind}:\{value t}") last toks com ops
+    Nil => Fail False (perror col.file toks "\{msg} at EOF") last toks com ops


 some : ∀ a. Parser a -> Parser (List a)
@@ -154,34 +143,50 @@ sepBy s a = _::_ <$> a <*> many (s *> a)


 getPos : Parser FC
-getPos = P $ \toks com ops indent => case toks of
-  Nil => OK emptyFC toks com ops
-  (t :: ts) => OK (MkFC indent.file (getStart t)) toks com ops
+getPos = P $ \last toks com ops indent => case toks of
+  Nil => OK (MkFC indent.file last) last toks com ops
+  (t :: ts) => OK (MkFC indent.file t.bounds) last toks com ops
+
+tokStart : TokenList → Bounds
+tokStart Nil = emptyBounds
+tokStart (t :: ts) = t.bounds
+
+bounded : ∀ a. Parser a → Parser (WithBounds a)
+bounded pa = P $ \last toks com ops indent =>
+    case runP pa last toks com ops indent of
+      (OK a last toks' com ops) => (OK (MkBounded a (tokStart toks + last)) last toks' com ops)
+      (Fail fatal err last toks x ops) => Fail fatal err last toks x ops
+
+withFC : ∀ a. Parser a → Parser (FC × a)
+withFC pa = P $ \last toks com ops indent =>
+    case runP pa last toks com ops indent of
+      (OK a last toks' com ops) => OK ((MkFC indent.file $ tokStart toks + last), a) last toks' com ops
+      (Fail fatal err last toks x ops) => Fail fatal err last toks x ops
+

 -- Start an indented block and run parser in it

 startBlock : ∀ a. Parser a -> Parser a
-startBlock (P p) = P $ \toks com ops indent => case toks of
-  Nil => p toks com ops indent
+startBlock (P p) = P $ \last toks com ops indent => case toks of
+  Nil => p last toks com ops indent
  (t :: _) =>
    -- If next token is at or before the current level, we've got an empty block
    let (tl,tc) = getStart t in
-    let (MkFC file (line,col)) = indent in
-    p toks com ops (MkFC file (tl, ite (tc <= col) (col + 1) tc))
+    let (MkFC file (MkBounds line col _ _)) = indent in
+    p last toks com ops (MkFC file ((ite (tc <= col) (MkBounds tl (col + 1) 0 0) t.bounds)))

 -- Assert that parser starts at our current column by
 -- checking column and then updating line to match the current

 sameLevel : ∀ a. Parser a -> Parser a
-sameLevel (P p) = P $ \toks com ops indent => case toks of
-  Nil => p toks com ops indent
+sameLevel (P p) = P $ \last toks com ops indent => case toks of
+  Nil => p last toks com ops indent
  (t :: _) =>
    let (tl,tc) = getStart t in
-    let (MkFC file (line,col)) = indent in
-    if tc == col then p toks com ops (MkFC file (tl, col))
-    else if col < tc then Fail False (perror file toks "unexpected indent") toks com ops
-    else Fail False (perror file toks "unexpected indent") toks com ops
-
+    let (MkFC file (MkBounds line col _ _)) = indent in
+    if tc == col then p last toks com ops (MkFC file t.bounds)
+    else if col < tc then Fail False (perror file toks "unexpected indent") last toks com ops
+    else Fail False (perror file toks "unexpected indent") last toks com ops

 someSame : ∀ a. Parser a -> Parser (List a)
 someSame pa = some $ sameLevel pa
@@ -193,12 +198,12 @@ manySame pa = many $ sameLevel pa
 -- check indent on next token and run parser

 indented : ∀ a. Parser a -> Parser a
-indented (P p) = P $ \toks com ops indent => case toks of
-  Nil => p toks com ops indent
+indented (P p) = P $ \last toks com ops indent => case toks of
+  Nil => p last toks com ops indent
  (t :: _) =>
    let (tl,tc) = getStart t
-    in if tc > fcCol indent || tl == fcLine indent then p toks com ops indent
-    else Fail False (perror indent.file toks "unexpected outdent") toks com ops
+    in if tc > fcCol indent || tl == fcLine indent then p last toks com ops indent
+    else Fail False (perror indent.file toks "unexpected outdent") last toks com ops

 -- expect token of given kind

--- a/src/Lib/Syntax.newt
+++ b/src/Lib/Syntax.newt
@@ -31,8 +31,6 @@ instance HasFC Pattern where
  getFC (PatWild fc _) = fc
  getFC (PatLit fc lit) = fc

-- %runElab deriveShow `{Pattern}
-
 Constraint : U
 Constraint = (String × Pattern)

--- a/src/Lib/Token.newt
+++ b/src/Lib/Token.newt
@@ -1,28 +1,7 @@
 module Lib.Token

 import Prelude
-
-record Bounds where
-  constructor MkBounds
-  startLine : Int
-  startCol : Int
-  endLine : Int
-  endCol : Int
-
-
-instance Eq Bounds where
-  (MkBounds sl sc el ec) == (MkBounds sl' sc' el' ec') =
-      sl == sl'
-   && sc == sc'
-   && el == el'
-   && ec == ec'
-
-
-record WithBounds ty where
-  constructor MkBounded
-  val : ty
-  bounds : Bounds
-
+import Lib.Common

 data Kind
  = Ident
@@ -98,3 +77,6 @@ value (MkBounded (Tok _ s) _) = s

 getStart : BTok -> (Int × Int)
 getStart (MkBounded _ (MkBounds l c _ _)) = (l,c)
+
+getEnd : BTok -> (Int × Int)
+getEnd (MkBounded _ (MkBounds _ _ el ec)) = (el,ec)
--- a/src/Lib/Tokenizer.newt
+++ b/src/Lib/Tokenizer.newt
@@ -52,13 +52,13 @@ quoteTokenise ts@(TS el ec toks chars) startl startc acc = case chars of
        '}' :: cs =>
          let tok = MkBounded (Tok EndInterp "}") (MkBounds el ec el (ec + 1))
          in quoteTokenise (TS el (ec + 1) (toks :< tok) cs) el (ec + 1) Lin
-        cs => Left $ E (MkFC "" (el, ec)) "Expected '{'"
+        cs => Left $ E (MkFC "" (MkBounds el ec el ec)) "Expected '{'"
  -- TODO newline in string should be an error
-  '\n' :: cs => Left $ E (MkFC "" (el, ec)) "Newline in string"
+  '\n' :: cs => Left $ E (MkFC "" (MkBounds el ec el ec)) "Newline in string"
  '\\' :: 'n' :: cs => quoteTokenise (TS el (ec + 2) toks cs) startl startc (acc :< '\n')
  '\\' :: c :: cs => quoteTokenise (TS el (ec + 2) toks cs) startl startc (acc :< c)
  c :: cs => quoteTokenise (TS el (ec + 1) toks cs) startl startc (acc :< c)
-  Nil => Left $ E (MkFC "" (el, ec)) "Expected '\"' at EOF"
+  Nil => Left $ E (MkFC "" (MkBounds el ec el ec)) "Expected '\"' at EOF"

  where
    stok : BTok
@@ -78,7 +78,7 @@ rawTokenise ts@(TS sl sc toks chars) = case chars of
      Right (TS sl sc toks chars) => case chars of
        '"' :: cs => let tok = mktok False sl (sc + 1) EndQuote "\"" in
          rawTokenise (TS sl (sc + 1) (toks :< tok) cs)
-        cs => Left $ E (MkFC "" (sl, sc)) "Expected '\"'"
+        cs => Left $ E (MkFC "" (MkBounds sl sc sl sc)) "Expected '\"'"

  '{' :: '{' :: cs =>
    let tok = mktok False sl (sc + 2) Keyword "{{" in
@@ -87,7 +87,7 @@ rawTokenise ts@(TS sl sc toks chars) = case chars of
      Right (TS sl sc toks chars) => case chars of
        '}' :: '}' :: cs => let tok = mktok False sl (sc + 2) Keyword "}}" in
          rawTokenise (TS sl (sc + 2) (toks :< tok) cs)
-        cs => Left $ E (MkFC "" (sl, sc)) "Expected '}}'"
+        cs => Left $ E (MkFC "" (MkBounds sl sc sl sc)) "Expected '}}'"

  '}' :: cs => Right ts
  '{' :: cs =>
@@ -97,7 +97,7 @@ rawTokenise ts@(TS sl sc toks chars) = case chars of
      Right (TS sl sc toks chars) => case chars of
        '}' :: cs => let tok = mktok False sl (sc + 1) Symbol "}" in
          rawTokenise (TS sl (sc + 1) (toks :< tok) cs)
-        cs => Left $ E (MkFC "" (sl, sc)) "Expected '}'"
+        cs => Left $ E (MkFC "" (MkBounds sl sc sl sc)) "Expected '}'"

  ',' :: cs => rawTokenise (TS sl (sc + 1) (toks :< mktok False sl (sc + 1) Ident ",") cs)
  '_' :: ',' :: '_' :: cs => rawTokenise (TS sl (sc + 3) (toks :< mktok False sl (sc + 3) MixFix "_,_") cs)
@@ -125,7 +125,7 @@ rawTokenise ts@(TS sl sc toks chars) = case chars of
    isUIdent c = isIdent c || c == '.'

    doBacktick : TState -> SnocList Char -> Either Error TState
-    doBacktick (TS l c toks Nil) acc = Left $ E (MkFC "" (l,c)) "EOF in backtick string"
+    doBacktick (TS l c toks Nil) acc = Left $ E (MkFC "" (MkBounds l c l c)) "EOF in backtick string"
    doBacktick (TS el ec toks ('`' :: cs)) acc =
      let tok = MkBounded (Tok JSLit (pack $ acc <>> Nil)) (MkBounds sl sc el ec) in
      rawTokenise (TS el (ec + 1) (toks :< tok) cs)
@@ -144,7 +144,7 @@ rawTokenise ts@(TS sl sc toks chars) = case chars of
    lineComment (TS line col toks (c :: cs)) = lineComment (TS line (col + 1) toks cs)

    blockComment : TState -> Either Error TState
-    blockComment (TS line col toks Nil) = Left $ E (MkFC "" (line, col)) "EOF in block comment"
+    blockComment (TS line col toks Nil) = Left $ E (MkFC "" (MkBounds line col line col)) "EOF in block comment"
    blockComment (TS line col toks ('-' :: '/' :: cs)) = rawTokenise (TS line (col + 2) toks cs)
    blockComment (TS line col toks ('\n' :: cs)) = blockComment (TS (line + 1) 0 toks cs)
    blockComment (TS line col toks (c :: cs)) = blockComment (TS line (col + 1) toks cs)
@@ -167,7 +167,7 @@ rawTokenise ts@(TS sl sc toks chars) = case chars of
 tokenise : String -> String -> Either Error (List BTok)
 tokenise fn text = case rawTokenise (TS 0 0 Lin (unpack text)) of
  Right (TS trow tcol acc Nil) => Right $ acc <>> Nil
-  Right (TS trow tcol acc chars) => Left $ E (MkFC fn (trow, tcol)) "Extra toks"
+  Right (TS trow tcol acc chars) => Left $ E (MkFC fn (MkBounds trow tcol trow tcol)) "Extra toks"
  Left (E (MkFC file start) str) => Left $ E (MkFC fn start) str
  Left err => Left err

--- a/src/Lib/Util.newt
+++ b/src/Lib/Util.newt
@@ -34,8 +34,8 @@ splitTele = go Nil



-getBaseDir : String → String → M (String × QName)
-getBaseDir fn modName = do
+getBaseDir : String → FC → String → M (String × QName)
+getBaseDir fn fc modName = do
  let (path, modName') = unsnoc $ split1 modName "."
  let parts = split1 fn "/"
  let (dirs,file) = unsnoc parts
@@ -44,9 +44,9 @@ getBaseDir fn modName = do
  let parts = split1 fn "/"
  let (dirs,file) = unsnoc parts
  let (path, modName') = unsnoc $ split1 modName "."
-  unless (modName' == name) $ \ _ => error (MkFC fn (0,0)) "module name \{modName'} doesn't match \{name}"
+  unless (modName' == name) $ \ _ => error fc "module name \{modName'} doesn't match \{name}"
  let (Right base) = baseDir (Lin <>< dirs) (Lin <>< path)
-    | Left err => error (MkFC fn (0,0)) err
+    | Left err => error fc err
  let base = if base == "" then "." else base
  pure (base, QN path modName')
  where
--- a/src/Main.newt
+++ b/src/Main.newt
@@ -217,13 +217,13 @@ processFile fn = do
  log 1 $ \ _ => "\{show dir} \{show name} \{show ext}"

  (Right src) <- liftIO {M} $ readFile fn
-    | Left err => error (MkFC fn (0,0)) "error reading \{fn}: \{show err}"
+    | Left err => error (emptyFC' fn) "error reading \{fn}: \{show err}"
  let (Right toks) = tokenise fn src
    | Left err => throwError err
  let (Right ((nameFC, modName), _, _)) = partialParse fn parseModHeader emptyMap toks
    | Left (err,toks) => throwError err

-  (base,qn) <- getBaseDir fn modName
+  (base,qn) <- getBaseDir fn nameFC modName

  -- declare internal primitives